You’re hanging onto a rock face 40 feet above the ground, shaking with exertion. The only parts of you resting on anything solid are the edges of your shoes and the tips of your fingers.

Your arms are burning, your core is tight, and the corded muscles in your forearms are standing out with strain. Your back muscles swell and roll as you pull yourself up to lodge your fingers in another tiny crevice in the rock. You reset your feet, tense your body, and pull again, and again.

Five more feet, 10 more feet, 20 more—and you’ve made it.

As your rope takes your weight, and your partner lowers you to the ground, your forearms are swollen and pumped, your fingers are shaking, and you wonder whether you can still raise your arms above your head. Yet you feel exhilarated and victorious.

Whether you’ve just done your first climb or your thousandth, you’re likely to be stiff the next morning. The human body is not designed for sustained vertical rock climbing.

Improving at rock climbing means pushing the limits of what you think your body is capable of achieving. Good climbers are some of the most-fit individuals in sports.

Rock climbing sits at an interesting juncture between hobby and exercise. Viewed from one angle, it is a sport that demands rigorous physical training and sacrifice from its participants, as well as a certain manic bravado.

Hemingway famously remarked: “Auto racing, bull fighting, and mountain climbing are the only real sports. … All others are games.”

From another perspective, rock climbing has become one of the world’s more-accessible fitness hobbies due to the proliferation of indoor climbing gyms, outdoor guide services, and willing participants.

Broad accessibility has led rock climbing to become one of the fastest-growing sports in the world. New climbers are flocking to climbing gyms and crags by the thousands.

Many new climbers are individuals simply looking for a great workout. They want to feel the burn that happens when you’ve gone 5 feet higher than you thought you could. Or they want to develop the strength a climber needs to hang by his arms as he swings his feet up level with his face.

There are a number of fitness benefits that climbing can afford, and these benefits are accessible to anybody looking to get a little adventurous and have a lot of fun.

Most of the benefits of climbing hinge on the fact that it requires you to use your muscles in unconventional ways. Again, intense rock climbing is not natural to the human form. If we were built to climb, we would look more like chimpanzees.

Rock climbing requires you to develop muscle systems that are often used to very different ends in our daily lives and even in our other workouts. In other words, rock climbing stresses an uncommon use of common muscles.

To give an example, when we climb everyday objects such as ladders, we are most often curling our hands around bars to pull ourselves higher. Consequently, most non-climbers expect climbable rocks to be similar to a series of easy-to-grip rungs. In reality, however, your hands must adjust to a variety of grips when rock climbing.

In climbing slang, climbers are faced with “slopers,” “jugs,” “pinches,” “crimps,” and “pockets.” You might have to pull yourself up on an edge as slim as a pencil or a handhold like a huge, rounded ball. You might even have to use a hole in the rock that is big enough for only one or two fingers.

Such grip positions are happening as you move your body weight up a vertical wall. The stresses put on your hands when adjusting to the limitless rock options presented by climbing will force your forearms, finger muscles, and finger tendons to strengthen tremendously.

In the Discovery Channel series “More Than Human,” 15-year-old professional climber Tori Allen, who weighed only 110.8 pounds, registered a grip strength of 36 kilograms (39.4 pounds). A sports physician noted that it was “the same grip strength you might see in an NFL football player.”

Something to keep in mind about rock climbing is that it is a body-weight exercise. As is the case with most body-weight exercises, climbing recruits a wide range of muscles for each movement. As you move your body up a rock wall, your fingers grip, your forearms tense, your biceps and triceps flex, your back muscles engage, your core moves, and your legs push.

Weight training, on the other hand, often seeks to isolate a single muscle group, to the disadvantage of things like the smaller, stabilizer muscles that you need to make controlled full-body moves. Muscular bulk only serves to impede climbing, though, so your body responds to the physical stress of the kind of full-body movement used in climbing by building lean, supple muscle.

Climbing sometimes requires movements that engage your muscles in unique ways. For example, you might be on an overhanging wall and have to pull halfway up with your right arm until it’s at a right angle, then stop, “lock off” that arm, and reach with your left.

With this type of movement, your core is engaged to keep your hips close to the wall. Your right arm and back muscles (especially the latissimus dorsi muscle) move dynamically to hoist yourself up, then freeze in an isometric contraction to lock your body position while your left arm reaches.

This is a simple example. Other types of climbing movements recruit the oblique, deltoid, and trapezius muscles, as well as a host of other smaller, stabilizing muscles.

Climbing requires body tension as well as dynamic movement. You will approach some moves by keeping most of your body still, and some moves by throwing for the next hold forcefully and quickly.

No other sport forces your muscles to constantly switch from isometric, static contractions to dynamic motions as climbing does.

Your body will respond differently to different styles of climbing. “Bouldering” is done on short rocks or walls and emphasizes the extremes of climbing strength in short climbs. “Top roping” and “sport climbing” occur on tall walls and cliffs and tend to emphasize power endurance.

The longer the climb, the more anaerobic endurance systems are engaged. Bouldering routes or “problems” consist of a few extremely powerful moves, while longer forms of climbing are composed of less-intense moves that must be sustained for a longer period of time.

The name of the game with long routes is “power endurance.” You have to continue making high-intensity moves and pushing through muscle burn for the duration of a sport or top-roped route, which can be over 100 feet.

The alternative is, of course, falling. This brings up the most-intangible fitness benefit that climbing can offer. No weightlifter or treadmill runner and no one in an aerobics class or a yoga session can say that he or she has performed under the pressure of fear.

Succeeding in doing one last arm curl in the gym is a far cry from succeeding at the crux move of a hard route when you’re hanging 50 feet off the ground. Both take a certain amount of mental fortitude, but only the climber has to face the real possibility of falling if he does not complete his next move.

Anyone climbing smart is also climbing safe. An immense amount of technology and planning goes into every piece of safety gear designed to save you when you fall, but there is always that tiny moment of uncertainty and fear that happens when your hands finally slip from the rock.

Climbing past the fear of falling is a great undertaking, and performing a physical task as complex and demanding as climbing while working through that fear is a true achievement. Everyone who climbs long enough gets over such fear, but it’s a demand imposed by few other kinds of exercise.

The bottom line is that rock climbing will increase your fitness whether you do it regularly or only occasionally. For many people, climbing is their chief form of exercise. However, it also makes a great cross-training option for those whose primary physical fitness goals center on aerobic exercise or weightlifting.

If you are interested in trying rock climbing for the first time, all you have to do is look up your local climbing gym and give a call. Indoor rock climbing is a great segue into climbing outdoors, and most seasoned outdoor climbers use indoor gyms to train and stay in shape.

Although this article stresses the fitness benefits, climbing is much more than an exercise regimen. Climbing is exciting, challenging, and fun to do by yourself or with friends. So if you want to select a new occasional hobby, then give rock climbing a try.

Focus on the fun, and the fitness will follow.

Cameron Little is the digital media manager of the Brooklyn Boulders Climbing Gym.